1. Field of the Invention
The present invention relates to a method for manufacturing an ink jet head that performs recording, which is used for a printer, a video printer, or the like as an output device of a copying machine, a facsimile equipment, a word processor, a host computer, or the like. The invention also relates to a method of manufacture therefor. In this respect, recording includes the provision of ink (printing) on cloth, thread, paper, sheet material, or the like, and also, includes not only the printing of characters but also, that of pictorial images, such as patterned images.
2. Related Background Art
The ink jet printing method has an extremely small amount of noises at the time of printing, and is capable of performing high-speed printing. This printing method makes it easier to execute color printing in a compact form. As one of ink jet printing methods, there is one type that ink is bubbled by means of heat generating element, and ink is discharged utilizing the growth of the bubble. FIG. 1 shows schematically one example of the conventional ink jet head H used for the type of the kind.
In FIG. 1, a reference numeral 4 designates a flexible wiring substrate; 5, external connecting terminals; 6, a wiring substrate; 7, a structural member; 10, a substrate for forming electrothermal converting element; 20, a nozzle structural member, which is a complexly formed structure; and 21, a discharge port.
FIG. 2 is an enlarged perspective view that shows the discharge element T of the ink jet head H represented in FIG. 1. This discharge element T is referred to the ink jet head disclosed in the specification of Japanese Patent Laid-Open Application 09-118017 filed by Lexmark Inc. in USA, for example. FIGS. 3, 4, 5, 6 and 7 are views that illustrate the manufacturing process thereof.
FIG. 3 shows the section of the nozzle structural member 20 in a stage prior to manufacture, which is formed by polymer film material 22 and adhesive layer 23. The polymer film material 22 is polyimide, fluorocarbon, polysulfone, polycarbonate, polyester, or the like. Preferably, it is polyimide.
Next, as shown in FIG. 4, the protection layer 24 is formed on the adhesive layer 23.
As a water repellent film formed on the ink discharge surface side, for example, it is preferable to form a polymer film having silicon or fluorine atom. Also, it is a technique generally used that a protection layer 24 is formed in advance on the water repellent film or the adhesive layer 23, and after laser processing, the protection layer 24 is removed so as to easily remove such by-product (debris, fragment) as has been produced by laser processing.
As one preferable example of the protection layer, there can be cited means for coating water soluble resin, such as PVA, disclosed in the specification of the aforesaid Japanese Patent Laid-Open Application 09-118017. For the coating of such resin film, the polymeric material is dissolved in advance in a solvent that may dissolve it, and applied by means of solvent coating method in general. As the solvent coating method, there is spin coat, bar coat, gravure roll coat, spray coat, or the like.
Next, laser processing is conducted through a mask, and ink flow path 26 and discharge port 21 are formed as shown in FIG. 5. At this juncture, the by-product 40 is produced simultaneously with the laser processing, which adheres to the protection layer 24. Next, with the removal of the protection layer 24, such by-product 40 is also removed. Then, as shown in FIG. 6, the adhesive layer 23 of the nozzle structural member 20 and the substrate 10, which is manufactured by means of semiconductor process, are bonded to form the discharge element T as shown in FIG. 7.
Also, FIG. 8 shows an ink jet head the structure of which differs from the one described above.
FIG. 9 is a cross-sectional view that shows the ink jet head represented in FIG. 8, which is formed by a ceiling plate member 102, liquid flow path, a heater substrate 101. A plurality of heat generating resistive members 105 is arranged for the heater substrate 101.
Also, FIG. 10 is a cross-sectional view that schematically shows an ink jet head the discharge efficiency and refilling characteristic of which are enhanced. This ink jet head comprises a ceiling plate member 102, movable member 120, upper displacement regulating member 122, and a heater substrate 101. A plurality of heat generating resistive members 105 is arranged for the heater substrate 101. The heat generating resistive member 105 is heated, and energy exerted by the bubbling of ink enables the movable member 120 to move. With the upper displacement regulating member 122 that regulates the upper displacement of the movable member 120, it is intended to make the bubble energy more efficient. For the ink jet head shown in FIG. 10, the liquid chamber and ink supply hole are formed for the ceiling plate member 102 as in FIG. 9 by means of Si anisotropic etching or blast processing.
As shown in FIG. 9 or FIG. 10, when liquid flow path is formed on the heater substrate, a substance of epoxy resin composition of liquid photo-cation curing type is coated on the substrate by spin coating method or the like, and then, the flow path is formed by the photolithographic technique using ultraviolet ryas or the like. After the liquid flow path is formed on the heater substrate, the ink jet discharge element bonded with the ceiling plate member is obtained, to which the orifice plate is adhesively bonded to obtain an ink jet head. Conventionally, a substance composed of thermo-curing epoxy resin has been used for bonding the heater substrate and the ceiling plate member.
For the structure described above, the adhesive is required to provide high resistance to ink and heat, because it is in contact with ink. Therefore, this agent is formed by epoxy resin. However, the epoxy resin adhesive is fundamentally composed of two component, main agent and curing agent. As a result, viscosity may change after mixture to make it extremely difficult to retain the mixture stably. This suggests a specific time limit for the process in which the adhesive is prescribed, coated, and used for bonding, which tends to lead to the lower productivity. If acid anhydride, imidazole, or the like is used as curing agent, the curing capability of epoxy resin is lowered to make the preserving stability higher. There is, however, a need for giving a high curing temperature for a long time. As a result, in a case of an ink jet head at least having the member, which is provided with a discharge port formed by polymeric film 22, the positional displacement may occur between the discharge port 21 and heater due to the difference in the linear expansion coefficient thereof with that of the substrate 10.
Also, when bonding is made by use of the substance composed of thermo-curing epoxy resin, the epoxy resin is soften and melted at the time of curing, and in some cases, the melted resin flows along the liquid flow path walls to clog the flow path, thus causing defective discharge. Particularly, in the case where movable member exists as shown in FIG. 10, the melted epoxy resin flows by means of capillary force to bury the circumference of the structural member, hence causing the movement of the movable member to be disabled sometimes.
To deal with the problems discussed above, there is a disclosure in the specification of Japanese Patent Laid-Open Application 09-24613 that the two members are bonded by use of epoxy resin of UV cation curing type so as to reduce the influence that may be exerted by heat. The flow of bonding process is shown in FIGS. 11A, 11B, 11C, 11D and 11E. Adhesive 23 is coated on the substrate 1 (FIG. 11A), and UV is irradiated through a mask 30 (FIG. 11B). Next, heating is given, and development is made (FIG. 11C). Then, after the fine pattern, which is formed by adhesive, is composed, another member 31 is bonded (FIG. 11D), and heated under pressure to perform the regular curing (FIG. 11E). This bonding method is effective means when the thickness of adhesive is 20 xcexcm to 30 xcexcm.
In recent years, however, the ink jet head becomes highly precise along with the demand on the higher quality of recorded images, and the thickness of adhesive is required to be smaller accordingly. Now, the thickness of the adhesive is made less than 20 xcexcm, for example, for the experiment and studies, and the following is found. In other words, in the process of beam irradiation needed for the formation of fine pattern, the curing reaction of epoxy resin advances greatly to the extent that the adhesive has almost no flowability when bonding is processed. Consequently, only an extremely small bonding strength is obtainable.
Also, the UV-cation curing epoxy adhesive is effective when applied to the material that transmits ultraviolet rays. It is known, however, that this agent does not effectuate bonding in good condition in some cases if applied to the material that does not transmit ultraviolet rays.
The present invention is designed in consideration of these problems. It is an object of the invention to provide a method for manufacturing an ink jet head, to which is applicable the adhesive having ultraviolet curing cation polymeric starter and epoxy resin contained therein, with excellent stability of preservation, and which makes it not only possible to implement high resistance to ink and heat after the adhesive has been cured, but also, to position the ink discharge port and the electrothermal converting element on the substrate in high precision at low bonding temperature.
The present invention is able to solve the aforesaid problems by means of the technical formation given below. In other words, the method of the present invention for manufacturing an ink jet head by bonding with liquid-like adhesive a member at least having a discharge port for discharging ink, and a substrate having an energy generating element to generate energy for discharging ink comprises the steps of coating the liquid-like adhesive on the member or the substrate, the liquid-like adhesive containing at least ultraviolet curing cation polymeric starter and epoxy resin; irradiating ultraviolet rays to the liquid-like adhesive to activate the ultraviolet curing cation polymeric starter; positioning the member and the substrate without heating process; and heating in a state of the member and the substrate being positioned to cure the activated liquid-like adhesive.
Also, the thickness of the adhesive layer is 10 xcexcm or less.
Also, the aforesaid ultraviolet curing cation polymeric starter is aromatic onium salt.
Also, the aforesaid liquid-like adhesive contains agent for providing flexibility.
Also, the member and the substrate are formed by material having Si as the main component thereof.
Also, the ultraviolet ryas are beams of wavelength of 380 nm or less.
Also, at least either one of the member and the substrate is formed by opaque material to the beam having wavelength of 380 nm or less.
Further, the method of the present invention for manufacturing an ink jet head by bonding with solid adhesive a member at least having a discharge port for discharging ink, and a substrate having an energy generating element to generate energy for discharging ink comprises the steps of coating adhesive on the member or the substrate, the solid adhesive containing at least ultraviolet curing cation polymeric starter and epoxy resin; irradiating ultraviolet rays to the liquid-like adhesive to activate the ultraviolet curing cation polymeric starter; positioning the member and the substrate without heating process; and heating the activated solid adhesive in a state of the member and the substrate being positioned to perform curing, while melting the solid adhesive.
Also, the melting point of epoxy resin of the aforesaid solid adhesive is 50xc2x0 C. or more and 120xc2x0 C. or less.
Further, the method of the present invention for manufacturing an ink jet head by forming a complex structure having at least adhesive layer on polymeric film material, and bonding the structure with the substrate having an electrothermal converting element formed therefor after forming more than one discharge port, ink flow path, and liquid chamber by performing laser processing to the complex structure comprises the steps of laminating the adhesive layer containing at least ultraviolet curing cation polymeric starter and epoxy resin on the polymeric film material; forming more than one discharge port by laser irradiation on the polymeric film material having the adhesive layer laminated; activating the ultraviolet curing cation polymeric starter by irradiating ultraviolet rays to the adhesive; positioning the member and the substrate without heating process; and heating in a state of the member and the substrate being positioned to cure the activated adhesive.
Further, the method of the present invention for manufacturing by bonding with adhesive a member at least having a discharge port for discharging ink, and a substrate having an energy generating element to generate energy for discharging ink comprises the steps of producing a dry film of the adhesive containing at least ultraviolet curing cation polymeric starter and epoxy resin; transferring the adhesive to the member or the substrate; activating the ultraviolet curing cation polymeric starter by irradiating ultraviolet rays to the adhesive; positioning the member and the substrate without heating process; and heating in a state of the member and the substrate being positioned to cure the activated adhesive.
Also, the ink jet of the present invention is the one manufactured by the aforesaid method for manufacturing an ink jet head.